Vehicle-wheel tire.



Patented Feb.27, 1917.

2 SHEETS-SHEET l C. S. BURTON.

VEHICLE WHEEL TIRE.

APPLICATION FILED sEI T 2I, I9I4.

Patented Feb. 27

2 SHEETS-SHEET 2.

rricn.

, CHARLES S. BURTON, lOF OAK PARK, ILLINOS.

VEHICLE-WHEEL TIRE.

Speoicaton of Letters Patent.

Patented ren. 2a, ier?.

Application iledSeptember 21, 1914. Serial No. 862,634.

To all whom t may concern Be it known that Criiiizmis S. BURTON, acitizen ofthe UnitedStates, residing at Oak Park, in the county of Cookand State of illinois, have invented new and useful Improvements inVehicle-lVheel Tires, of which the following is a specification,reference being had to the accompanying drawings, forming a partthereof.

The purpose of this invention is to provide an improved construction ofa vehicle wheel tire of the character comprising the cushioning ti'eadmember and adapted also to comprise a pneumatic air spring' interior tothe tread member. lt consists in the elements and features ofconstruction shown and described Aas indicated in the claims.

In the drawings: e.

Figure l is a side eleva-tionof a fragment of a lwheel and tireembodying this invention, the tire-retaining lateral guard being partlybroken away.

Fig. 2 is a section at the line 2, 2, on Fig. l.

Fig. 3 is a section at the line, 3, 3, on Fig. l.

Fig. 4 is a side elevation of a segment of the rubber tread member andVassociated reinforcing and draft-transmitting links, the primary draftlink being removed.

Fig. 5 is a side elevation of the rubber tread member with all of thelinks removed.

Fig. 6 is an end View of one of the drafttransmitting links. l

Fig. 7 is an end view of one of the primary draft-links.

Fig. 8 is a section of link structure at the curved line, 8, S,` onFig.y 1.,.

In the tires shown-in the drawings above described, there are securedupon thefelly, l, of the wheel, lateral metal guards, 2, 2, formingbetween them a peripheral channel in which the-tire proper is retainedand seated. As illustrated in the drawing there is provided an airspring',- 3, whichis seated in this channel lat the bottom thereof, andl. b

draft links, which to distinguish them from upon which is seated thecushioning tread member, 4, said tread member being adapted to be seatedotherwise in vthe absence of the air spring, or when the air spring isdeflated and thereby prevented from supporting said tread member. Theparticular manner of securing the lateral guards, 2, 2, to the felly, l,and the particular strucying it with the lateral guards, 2, 2.

ture of the air spring, do not constitute features distinguishing thepresent invention.

tures of this invention relate to the form ofy the cushioning treadmember and the means for reinforcing it and connecting it with the wheelproper which iseffected by connect-h rlhe construction ofthe cushioningtread meinber, and its associated parts, and its draft connections, withthe lateral gu'ards will now'be described. l

The cushioning tread member, 4, is preferably made substantially all ofrubber or other similar resilient and flexible substance. It isdimensioned to' occupy sub- `AAny'method of securing the guards to the pstantially the entire space between the opposite lateral guards, 2, 2,outside of the space allotted to the air spring, and particularly it isdesigned and dimensioned to entirely occupy and close the peripheral gapbetween the outer circumferences of the opposite side `guards and isparallel-sided at the portion which enters between the pe-V ripherics ofthe side guards so that it may reciprocate radially with respect to thewheel between the side guards, as into the air spring which supports ityields radially under the load. For the purpose of transinittingrotar-yV movement between the tread member and `the lrigid parts of thewheel,

fincluding the sidegguards," .2, 2,-that is,

transmitting said rotary motion from the side guards .to the treadmember, when the wheels are the driving or traction wheels, andtransmitting `rotary motion from the tread member to the rlateral guardsand remainder of the wheel when rthe wheels are trailers or steeringwheels,'#that is, other than driving wheels-there are I provided otherlinks in the structure to be described, are herein termed the primarydraft links, 5, said primary draft 4links being pivoted at one end toone of the lateral guards, 2, 2, and at .the other end to the treadmember. Preferably at the normal position, that is, at the positionoccupied when the tread member is not compressed or forced inwardradially with respect to the lateral guards, these draft links extend indirections approximately tangential to the circle in which their pivotsto the lateral guards are located, so that in transmitting the rotarymotion or draft, either from the lateral guards to the tread member orfrom the tread member to the lateral guards, the links extend at rightangles to radii of the wheel. lthrough their respective pivots to thelateral guards. For pivoting these primary draft links to the lateralguards, 2, 2, the latter are furnished with rigid pivot studs,

G, projecting inwardly from the said lat-` eral guards; and for pivotingthe primary draft links,-to the tread member, there are preferablyembedded in the tread member, extending transversely therethrough metalsleeves, 7, into which the pivot studs or spindles, S, of thetread-meinber-end of the links, 5, are inserted, so that said embeddedmetal sleeves constitute journal bearings for the link pivots in thetread member.

Preferably the primary draft links, besides transmitting the rotarymovement from one to the other of the two members which they connect,are adapted to serve the purpose of limiting the radially outwardmovement of the tread member between the lateral guards. For thispurpose the lateral guards havetheir outer circumferential marginalportion turned laterally inward so as to overhang the lateral portion ofthe channel between the two guards, and the draft links being pivotedclosely adjacent to the inner surface of the lateral guard, are situatedin the portion of said channel which is thus overhang by the in-turnedflanges of the guard, and the ends of the draft links which are pivotedto the tread member are thereby positioned so that in the outwardmovement of the tread member, they are forced up against saidoverhanging flanges, and stopped against further outward movement andthereby stop the tread member. lt will be understood that when an airspring is comprised in the tire as illustrated, the inflation of thisair spring operates to force the tread member, t, radially outward whichwill seat the primary draft links, 5, as snugly up against theoverhanging flanges as the draft transmitting` links will permit. Foranother purpose about to be stated, the laterally in-turned flanges ofthe lateral guards are in-turned radially, that is, towa d the wheelaxle forming a lip, 2b, and forming a groove or channel, between twodifferent sides of the flange indicated by the reference letter, 2C. For convenience the entire laterally inturned flange comprising the lip,2b, is denoted by the reference character, 2a. The particular purpose offorming the in-turned lip, 2b, and thereby the groove, 2C, of thelateral guard, is to afford means for tying the two lateral guardstogether so that any side stresses or pulls to which they may besubjected,each may sustain the other. Such sideward pulls result intravel when the projecting portion of the tread member is crowdedlaterally which is caused in travel by obstructions in the road or byirregular ruts with which it may be engaged, or when the vehicle istraveling upon a side hill; and it is obviously important that thelateral guards do not become pcrmaiiently spread apart by theserccurring lateral stresses operating through the tread member. l? orthis purpose the primary draft links, are cach formed with a flange, orlug, 5, positioned opposite the pivot of the link which engages thetread member, and extending any distance desired thence toward the otherend; and the two opposite draft links have their pivots consisting ofthose spindles, either formed in one piece or connected together withinthe embedded metal sleeve which forms their journal bearing in the treadmember. YWhen thus connected it will be seen that the lugs, 5b, upon theopposite links engaged with the lips of the opposite lateral guards andconnected directly through the tread member, 5, by the unit-ed spindles,constitute complete ties from lateral guard tolateral guard operating toprevent the guards from being spread apart. lt will be also clear thatwhen the connection between the two pins or spindles of the primarydraft link is such as shown, that is, adapted to prevent the links frombeing pushed toward each other, as well as to prevent them being pulledapart,-the same connection described, not only operates to prevent thespreading apart of the lateral guards by a puik-that is` a pullingaction operating` upon either of them,but will also operate to preventthem from being crowded together by exterior pushing` upon either ofthem, and so prevent them from pinching the tread member between them. Aconvenient means of connecting` the pivot spindles of the draft linkswithin the em* bedded metal sleeves is to provide them in mutuallyengaging tlnreaded ends so that one 'may be screwed to the other. l/Yheuthis form of construction is adopted. it will be understood that theentire assemblage of the metal parts (comprising the draft links, andthe draft transmitting links hereinafter described) for both sides ofthe tread member will be completely organized and lodged in the mold inwhich the tread member is vulcanized; and it will be seen that thisavoids the obvious diiliculty which would arise in connecting togetherthe two opposite draft link spindles by screwing` as described, if thelinks were to be mounted on the tread meinber in the manner describedafter the tread member was vulcanized. The

tread member up and through the embedded beveled sleeves therein; andwith this construction it is equally convenient to form and vulcanizethe tread member with only the metal sleeves embedded therein and toapply the remaining metal fittings, the primary draft links and thedraft transmitting links hereinafter described, after the tread memberis completed and vulcanized. It will be noticed that the stoppage of thedraft links against the laterally inturned flange of the lateral guard,as mentioned above, occurs where the end of the lug, 5b, encounters thebottom of the groove, 2". j

Preferablyl in addition to the two sets of draft links describedsituated one at each side of the tread member, there is provided at eachside of the tread member an endless chain of draft-transmitting links,9, whose pivots are the pivot spindles, 8, of the primary draft links.These draft-transmitting chains are preferably partially embedded in thelateral faces of the tread member. They are, however', stopped againstlateral movement inward with respect to the tread member, and so areprevented from causing transverse compression of the tread member, bythe embedded metal sleeves, 7, against whose ends the inner-lapped endsof the links at each junction throughout the chain, abut.

In order to provide a wearing plate to take the friction of thein-turned flange or lip of the lateral guards against the lateral faceof the tread member, the boss, 9a, which constitutes an extension inwardof the innerlodged end of each draft-transmitting link, is extendedoutward radially with respect to the wheel, as a wearing plate, 9b, andlodged in a correspondingly extendedpocket in the side of the treadmember, and stands exposed Hush with the lateral face of the treadmember for a distance equal to the full stroke or play of the treadmember between the flanges under the load, that is, so as to cover theentire distance over which the in-turned lip or flange of the lateralguard might otherwise rub upon the lateral face of the tread member. Asillustrated, there are eighteen draft links at each side and eighteendraft-transmitting links, 9, so that there are provided in the abovedescribed construction eighteen wearing plates to take therubbingfriction of the in-turned flange of the metal guards at each side.

To reduce as much as possible the friction between the draft links andthe inner surface of the lateral guards, the draft links are slightlycut back at their outer surfaces throughout their length except as tothe end bosses about their pivots, thus reducing the frictional area tothe area of said bosses. The construction above described involving theoutwardly projecting bosses about the pivot of the outer lapped end ofthe draf*- transmitting link, results in leaving a space for clearancebetween the outer surfaces of said draft-transmitting links and theinner surfaces of the primary draft links throughout the whole length ofsaid primary draft links except so much at one end as abuts upon saidoutwardly projecting boss. This clearance besides avoiding frictionbetween the primary draft links and the draft transmitting links is aconvenience, in that it permits the extension of the pivot studs, G, bywhich the draft links are engaged with the lateral guards, that is, itpermits that the pivot studs should be longer than the thickness of thedraft links which are engaged with them to the extent, or nearly theextent, of the clearance mentioned., so that the studs project throughthe links into said space. This is a convenience in assembling the partsof the wheel, because it makes it possible to engage the draft linkswith their respective pivot studs and one at a time and before thelateral guard is forced fully into place against the tread member,whereas if said studs did not protrude farther than the thickness. ofthe draft links, it would be necessary to get accurate registration ofall the studs and all the draft links so that they might all enter atonce, before forcing the lateral guard home, which would be verydifficult to accomplish.

Preferably, the zone or annular area. occupied at each side of the treadmember by the link systems described, is situated a short distanceradially inward with respect to the inner circumferential edge of theinturned lip 2b, of the lateral guard, so as to permit the tread memberto be formed with its rubber substance extending past that lip and outinto the groove, 2,forming the lip, fig, which is circumferentiallyinterrupted only by the lugs, 5b. Such occupancy of the groove, 2, atthe inner side is desirable in order to prevent the access thereto ofwater, and particularly sand, which if it obtains easy entrance, mightbecome gradually packed in the groove and prevent the lugs, 5", frombeing thrust out into it as contemplated. Such positioning of the zoneoccupied by the link system, and extending the rubber as mentioned outpast the edge lip,

rubber, 4P, as thick in the direction of the wheel radius as the shortdistance above mentioned, and as wide as the thickness of the lip, 2b,(see Figs. 2 and 3), and, projecting radially out from the outer edge ofthat neck, segments of flanges whose circumferential extent covers theintervals in the groove, 2C, between the lugs, 5b. This is desirable inorder to prevent the space in the groove becoming filled with water, andparticularly with sand, which might become gradually packed in thegroove and prevent the lugs, 5b, from being thrust out into it ascontemplated. rlhis results in an annular neck of rubber, Lif, as thickin the direction of the wheel radius as the short distance abovementioned, and as wide as kthe thickness of the lip, 2b, and, projectingradially out from the outer edge of that neck, segmental flanges, eg,which fill the intervals in the groove, 2, between the lugs, 5h. It willbe observed also that the wearing` plate extensions, 9b, of the link, 9,lie in behind this annular neck, 4f, whose continuity with the body ofthe tread member is necessarily interrupted where the pocket whichaccommodates the wearing plate extension crosses the annular neck. Theseinterruptions, 4h, occurring directly opposite the intervals between thesegmental flanges, Ll?, reduce the neck at that point, that is for aboutan inch circumferentially of the wheel at each occurrence, to a slenderbridge of rubber ai, about one-eighth of an inch square in crosssection, which however serves the purpose of completing the closurewhich the neck is intended to make around the inner edge of the lip, 2b,to exclude water and sand or to occupy space which would otherwise tendto become filled with sand.

As the draft links swing at their ends which are pivoted on thespindles, 8, inward toward the wheel center when the load forces thetread member into it, their opposite ends being pivoted to the lateralguards and thus held without capacity for yielding` inward, theresulting deflection of said draft linksfrom the circle in which theynormally stand necessitates affording space for such deflection by meansof recesses, 4k, in the sides of the tread member, as shown in Figs. 4f.and 5.

The most convenient method of assembling the wheel is as follows:

The inner lateral guard is first securely mounted upon the felly and theair spring, if one is to be employed, is placed in position. The treadmember with all the metal elements described, that is all the linksystems mounted upon it, is now passed into position against the innerlateral guard, the pivot studs, 6, on the latter, being en- V'gaged withthe draft links on the inner side of the tread member, the projections,5b, on the draft links throughout the greater portion of the treadmember being engaged with the groove, 2C, in the peripheral flange ofsaid member by the easy expedient of springing the tread member, thelast few of said projections being forced into engagement by using amallet pounding radially upon the tread member while it is `pressedlaterally toward the lateral guard, until all of said projections havebeen sprung into place.

Certain details of the construction of these links remain to be noticed,being preferentialv only and of minor importance, but not negligible.

ln order to obtain adequate bearing of the draft-transmitting links uponthe pivot spindles of the primary draft links, without making saiddraft-transm-itting links thicker throughout their length, and soheavier, than necessary for their purpose, the innerlapped end. of eachof said transmitting links is formed with a lateral inwardly-protrudingboss, 9, around the pivot, which is seated in a pocket, ab, provided forit 1n the lateral face ofthe tread member el. For similar' purpose theouter-lapped end of each trai'ismitting link has an outwardly protrudingboss, 9d, to accommodate which the hub of the primary draft link isrecessed at the inner side. By these means each end of each of thedraft-transmitting links obtains bearing on the pivot spindle, 8, abouttwice as wide as the thickness of the link at the remainder of vitslength between said bosses.

Upon considering the structure above dcscribed, it will be understoodthat the draft link, 5, constitutes means by which the rotary impulsemay be communicated from the rigid portions of the wheel to the flexibleand more or less stretchable and compressible tread member, bysubstantially simultaneous engagement of the tread member at amultiplicity of points about its circumference instead of at a singlepoint, thus to a large extent eliminating the circumferential extensionand compression of the tread member in the traction, and thereby makingthe tread member much more promptly responsive to the rotary impulse,and reducing the waste of energy which tends to result from suchcompressibility and extensibility of an elastic tread member. ln order,however, to make this draft link oiganization most fully effective, itisdesirable to eliminate the stretching and compressing action which isliable Ato occur in transmitting the draft in the Vtread member fromeach pivotal connection of the draft link therewith to the next suchconnection. lt is fortliis purpose that the draft transmitting linksconstituting an endless chain upon each side of the tread member areprovided inv addition to the primary draft links.V

Upon Vconsideration of these endless chains of draft transmitting linksat each side of the tread member', it will be understood that if theywere proportioned so that each complete endless chain of said links whenpositioned in circular form, would be of such diameter, that the ends ofthe lugs, 5b, of the draft links, projecting from the pivots of thelinks of the chains with the same effect substantially as if theyprojected from the hubs of the links, 9, to the bottom of the groove,2c, of the lateral guard member, such endless chain would havesubstantially the effect of a rigid annular member engaged with thetread member, and would entirely defeat the flexibility of said tread Ymember', because no one junction or pivotal connection of such endlesschain coilld be forced radially inward without forcing outward one ormore other pivotal junctions, and since such outward movement would beprevented by the stoppage of the lugs, 5b, at the bottom of the groove,2c, of the lateral guard, inward movement would be prevented, so that nomovement would be possible. In order, therefore, that the endless chainof draft-transmitting links shall not defeat the flexibility of thetread member, the parts are so proportioned that when the pivots of theendless chains, which are the pivots of the draft links'in the treadmember, lie in a circle, a circle which would circumscribe the outerends of the lugs, 5b, is of enough less diameter than that of thelateral guard to the bottom of the groove, 2C, to permit the liatteningof that circle, by flexure at one or more of the joints of the endlesschain, to substantially the extent necessary to permitv the tread memberto yield inward radially with respect to the wheel to the extent towhich the air spring is adapted to be flattened under the load. ln theconstruction shown this distance is designed to be about g-ths of aninch in a wheel having its tread diameter 3G.

Upon furth conside 1ation, it will be seen that with the endless chainconstruction described, having the links arranged for flattening theendless chains before the links are stopped by the in-turned lip of thelateral guards, it will result that when the load is such as to forcethe tread mem ber inward until the maximum flattening of the endlesschains is caused, the endless chains thus flattened at one point intheir circumference at which the load operates. will have the effect ofa rigid moans of transmitting the load to the rigid metal lateralguards, 2, Q, and that no further inward movement of the tread membercan occuil except from the breaking or bending of one or more of thelinks or of their pivots.

' These links and their pivots are designed to be sufficiently strong tocarry the load under such conditions. rfliey therefore operate as themeans of limiting the compression which can be imposed upon the airspring. ln case the air. spring is deflated and does not operate as aspring, the tread member will be forced inward bythe load to the limitpermitted by the endless chains composed of the draft-transmittinglinks, as indicated, that is, flattening the chains at the lower side ofthe wheel where the load operates, and bringing the remainder of thecircumference of the endless chains into contact with the in-turned lipsof the lateral guards.

The same limitation of flattening by limitation of bulging, andsubstantial rigidity if the chains were not allfwed space for slightlybulging elsewhere when flattened at one part of the circumference, wouldresult from the links of the endless chain being stopped by the innercircumference of the in` turned lip, 2b, if the annular neck ofcompressible rubber, 3f, were not present; that is,

if the in-turned lip were extended through the space ,occupied by thatneck; and the presence of that neck for the purpose stated is the reasonfor relying onthe encounter of the lug, 5b, with the bottom of thegroove, 2C, for the desired limitation of flattening. With theconstruction shown, these lugs being relied upon for the functiondescribed, the rubber neck, 3f, may completelyl and snugly occupy theentire annular interval which is left between the outer circumference ofthe chain of links, 9, and the inner circumferential edge of the lip,5b; because the compressibility of the rubber will adequatelyaccommodate the necessary amount of flatten- .ing and bulging of thechains as described,

to permit a gth radial movement of the tread member at the point atwhich it is under the load.

Vlhen operating as above described without the air spring or with itdeflated, it will be seen that the tire operates in all respectssubstantially as a. pure cushion tire with the benefit of a cushionwhose depth or thickness is to be measured from the circle in which themetal sleeves, 7, are situated, outward to the tread circumference. Inorder to obtain the advantage of the remainder of the thickness of therubber tread member,that is, the portion from the sleeves, 7, inward tothe inner circumference of said tread mem' cle in which the embeddedmetal sleeves, 7,

are situated is safely susceptible.- By this means the full cushioningvalue of the tread member from inner to outer circumference is madeavailable before the load is transmitted positively7 by the endlesschains composed of draft-transmitting links to the rigid lateral guards,QI, 2, and before, therefore, the duty of carrying the load is imposedupon the links and their pivots.

In accordance with a practice approved by experience and not in itselfconstituting a part of the present invention, except in con binationwith other features above described, there are embedded in the innercircumference of the tread member, el, wooden blocks, l2, preferablyparatlin-treated for lilling the grain with a substance not deleteriouste rubber, said blocks protruding very slightly from the innercircumference of the tread to receive the contact cf the air spring. lnthis construction, these blocks perform an additional function oftransmitting transversely of the tread member the radially outwardpressure exerted by the air spring when expanded against such treadmember, so as to prevent the otherwise existing tendency of suchexpansion to bend the tread member transversely, and particularly tobend the embedded metal sleeves, and thereby distort the link pivots'outof their proper alinement. rlhe pockets formed inthe inner circumferenceofthe tread member to receive these blocks, 12, are traversed at theirbottoms by the embedded metal sleeves, r and the blocks arelongitudinally greoved to adapt them to accommodate said embedded metalsleeves when the blocks are inserted in the pockets. rlhis brings aboutan engagement of the blocks with the metal sleeves which tends toprevent any tendency which might otherwise arise of the blocks to betipped in their pockets by the action of the air spring upon their innersurfaces. T he length of the blocks is such as will leave adequatecushioning for their ends against any endwise movement,-that is,movement transversely of the tire, which may sometimes result from thefrictional engagement of the air spring with 'the blocks, The contour intransverse section of the tread member at its inner circumference fromthe ends of the blocks outward, is such that in radial section the innersurface of the tread member converges toward the surface of the ledges,10, so that the tread member strikes the ledge first at the outer sides,the contact of the tread member with 'thei'ledge extending from theouter sides inward compression proceeds. rlhe inclination of the innersurface of the tread member with respect to the surface of the ledgesoperates to cause the direction of the compression resulting from theencounter Vof the tread member with the ledge to be toward the ends ofthe blocks, i2, instead of radially outward; and by this means theelastic resistance of approximately the entire body of the rubbersituated inward from the metal sleeves, 7, is brought into service forcushioning the load before the limit of flattening of the endless chainsreached.

l claim:

l. n a vehicle wheel, in combination with lateral guards forming betweenthem a tire retaining channel, a tread member of cushioning materiallodged in such channel and constructed for movement therein of itsentire thickness toward and from the wheel axis under changes of loadand draft links pivoted at one end to the guards and at the other end tothe tread member and having their pivotal movement relatively to thetread member in planes parallel to 'the wheel, and extending from thefirst mentioned pivots approximately tangentially with respect to vthecircle in which said pivots are situated about the wheel axis.

2. ln a vehicle wheel, in combination with lateral guards, formingbetween them a tireretaining channel; a tread member of cushioningmaterial lodged in such channel; draft links at opposite sides of thetread member, each pivoted at one end to the lateral guard at that side,and at the other end to the tread member, and extending from the firstmentioned pivot approximately tangentially with respect to thecircumference of the circle about the wheel axis in which said pivot issituated; the corresponding links at opposite sides of the tread memberhaving their pivots extending into said tread member and connectedtogether,

' said draft links having means for engaging the lateral guards at theirrespective sides; whereby said links and their pivots constitute meansfor tying together the opposite lateral guards.

3. ln a vehicle wheel, incombination with lateral guards at oppositesides o f the tread, and forming between them a tire-retaining channel;a tread member of cushioning ma! terial lodged in such channel havingcnibedded in it and extending transversely through it, a multiplicity ofmetal tubes or sleeves and draft links pivoted at one end. to thelateral guards and having at the other end pivot spindles extending intoand obtaining bearing in said sleeves.

l. ln a vehicle wheel, in combination with lateral metal guards formingbetween them a tire-retaining channel, and having periph eral laterallyiii-turned ianges with radially iii-turned lips forming grooves facingthe axis of the wheel; a tread member of cushioning material lodged insaid channel between the lateral guards; two series of draft linkslocated between the guards at opposite sides of the tread member pivotedat one end therein, the respectively opposite draft links having theirpivots in the tread member connected to- CIK circumferential p gethertherein, the other ends of said links being pivoted to the lateralguards respectively, said links having at the outer side lugs projectingradially outward adapted for engaging said inwardly-opening grooves ofthe lateral guards.

5. In a vehicle wheel, in combination with opposite lateral guardsforming between them a tire-retaining channel, a tread member ofcushioning material lodged in such channel and constructed for movementtherein of its entire thickness toward and from the wheel axis underchanges of load; an endless chain of links lodged laterally with respectto the tread member; the pivots which connect consecutive links beingengaged with the tread member independently of any such engagementeffected by means of the links, and draft means connecting the linkswith the lateral guards at the sides of the tread at which the linksrespectively are located.

6. In a vehicle wheel, in combination with lateral guards formingbetween them a tireretaining channel, a tread member of cushioningmaterial lodged in such channel and constructed for movement therein ofits entire thickness toward and from the wheel axis under changes ofload; two endless chains of links lodged at the opposite sides of thetread member, the pivots of the corresponding links of the two chainsbeing extended through the tread member and thereby engaged with andconnected together and draft means connecting said pivots with thelateral guards.

7. In a vehicle wheel, in combination with lateral guards formingbetween them a tireretaining channel, a tread member of cushioningmaterial lodged in* such channel; metal sleeves embedded transversely inthe tread member; endless chains of links lodged at opposite sides ofthe tread member; draft links in two series, one at each side of thetread member, having their pivots at one end connected with the lateralguards respectively, and spindles or stems forming their pivots at theother end journaled in said transversely embedded sleeves, said lastmentioned pivots or stems constituting the pivots connecting the linksof said chains, respectively.

8. In a vehicle wheel, a flexible tread member of elastic cushioningmaterial, such as rubber; lateral guards between which such tread memberis retained; two endless chains positioned at opposite sides of thetread member between the lateral guards, and having the pivotsconnecting their links engaged with the tread member, the lateral guardshaving shoulders facing the wheel axis and in a. circle thereabout;means by which the pivots of the links of the chain are stopped by suchshoulder when moving away from the wheel axis, the circle in which saidencountering means are situated when disposed in a circle about thewheel axis, being of slightly less diameter than the circle defining theinwardly facing shoulder of the guard.

9. In a vehicle wheel, a flexible tread meml ber of elastic cushioningmaterial such as rubber; lateral guards between which such tread memberis retained; endless chains composed of links positioned at oppositesides of the tread member between the lateral guards; metal sleevesembedded in the tread member with which the pivots of said endlesschains are engaged, the lateral guards having each a circumferentialshoulder facing toward the axis of the wheel at the inner side,encompassing the chains respectively, and means by which the pivots of'the chain links are stopped by encounter with said shoulder to limitmovement away from the axis; the diameter of the lateral guards at saidcircumferential shoulder being slightly more than the diameter of acircle circumscribing the chain when positioned with the link pivots ina circle.

10. In a vehicle wheel, in combination with a flexible tread member ofelastic cushioning material such as rubber; lateral guards forming achannel in which said tread member is lodged; an air spring lodged insaid clr'annel within the tread member; anti-friction blocks lodged inthe inner circumference of the tread member for seating upon the airspring; metal sleeves embedded transversely in the tread member, andmeans engaging said sleeves for connecting the tread member with thelateral guards, said embedded sleeves being positioned radially outwardfrom the anti-frictionblocks, respectively, and the blocks having attheir inner sides each a groove for engagement with the embedded sleeve,whereby the blocks are prevented from being turned over in their seatsin the rubber tread member.

1l. In a vehicle wheel, in combination with a cushioning flexible andelastic tread member; lateral guards forming a channel between which thetread member is lodged; endless chains comprising links positioned atopposite sides of the tread member within the channel between thelateral guards, the link pivots of such chains being engaged with thetread member, the lateral guards having shoulders facing inwardly towardthe axis of the wheel, overhanging the chains respectively, anddimensioned to limit the flattening of the chains under the load, andthereby limit the movement of the tread member radially inward withrespect to the channel, said lateral guards having inwardly-extendingledges located normally inward from the innerv circumference of thetread member a distance somewhat less than that involved in theflattening of the chains Lernen? permitted by the relzit'ive dimensionsof said In testimony Whereof,1 have hereunto set chains and saidperipheral shoulder of the my hand at Chicago, Illinois, this 31st doylateral guards; whereby the inner eireumof August, 1914.

ferential portion of the tread member is CHARLES S. BURTON. Compressedunder the load after its lodg- Vitnesses: ment upon said ledges beforethe limit of LUCY I. STONE,

flattening of the chains is reached. EDNA M. MACNTOSH.

Copies of .this patent may be obtained. for five cents each, byaddressing the "Commissioner of Patents,

Washington. D. C.

